CVE-2026-73571Network attack vectorHinoki check available

Authenticated email impersonation via unchecked delegation

Published Aug 13, 2026 · Updated Aug 13, 2026

Incorrect authorization in Zimbra Collaboration before 10.1.17 allows remote authenticated users to send email as another user. The SaveDraftRequest SOAP handler accepts crafted delegated-send requests without verifying that the caller holds delegation or send-as permission. A valid account is required, and the reported consequence is limited to unauthorized outbound email under the impersonated identity.

CVSS severity3.1
Low
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
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Summary

What happened

Incorrect authorization in Zimbra Collaboration before 10.1.17 allows remote authenticated users to send email as another user. The SaveDraftRequest SOAP handler accepts crafted delegated-send requests without verifying that the caller holds delegation or send-as permission. A valid account is required, and the reported consequence is limited to unauthorized outbound email under the impersonated identity.

The record

CVE
CVE-2026-73571
Published
Aug 13, 2026
Updated
Aug 13, 2026
Vendor
Zimbra
Product
Zimbra Collaboration
Classifications
CWE-863, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 13, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 13, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <10.1.17

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Zimbra · Zimbra Collaborationversion=0 <10.1.17

Published CVSS scores

3.1MITRECVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-863Incorrect Authorization
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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